i've shot those and i can stand by the above statement. unless the promaster shoots like an EGO, newer timmy or angel then i'm pretty sure i'd like the ion over a promaster too. i don't like popet valve markers with large cycling mass. i hate the way they feel.

I highly disagree. But then again thats my opinion, and you have yours. I haven't shot all those guns, but its preference and obviously you like the Ion better than all of those. Shoot what you're considering buying and then decide.